Welshpool & Llanfair Light Railway, North Wales, UK
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Nigel Day & Shaun McMahon's initial work at the Welshpool & Llanfair Light Railway was so successful that the entire regular service fleet has been redraughted. The locomotives are now more powerful than before and consume less fuel to do the same job. The cost of the work was very quickly recovered by the WLLR. |
In
the December 1994 issue of the British railway publication Railway World
a very interesting article on the work at Llanfair was published. Click
here to read it. |
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In 1993 the first locomotive, No.14, was equipped with a Lempor exhaust system, steadily followed by the rest of the fleet.
The Modified Locomotives |
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No. 12 'Joan', which has not run for some years is now, the only member of the regular service fleet to not have been fitted with a Lempor. This is to be undertaken when the locomotive's current overhaul is completed. No.8 'Dougal', a very small shunting loco not suitable for open line work has also not been fitted with a Lempor; it being felt there is little point. No.6 'Monarch' is currently being given a cosmetic overhaul and is unlikely to run for a very long time, if ever again, so redraughting is not necessary. However this loco has served its purpose giving rise to the term the 'Monarch Syndrome' - reference to the appalling draughting system's performance on this loco.
The 'Monarch Syndrome' was explained by Nigel Day as:
"The exhaust steam does not fill the chimney. The result is that no seal is made (the steam must touch the inside of the chimney to make a seal) in the chimney so the vacuum produced by the entrapment in the exhaust steam is lost. You can see the smoke around the edge of the chimney being dragged back into the smokebox to fill the vacuum. As the smoke from the firebox has a greater resistance to over come it is evident that draught on the fire is non-existent. So all that happens is air is sucked down the chimney just to be pushed up--- a pointless exercise!
The reason it is called 'Monarch Syndrome' is that we first realised it was occurring on Monarch's chimney and hence that loco's bad steaming reputation. Most single nozzle chimneys have this problem to some extent."
Nigel has also provided a video showing something of this problem. W&LLR No.19 had been lit up but unlike the other locos in the fleet was not then equipped with the necessary pipework for compressed air to be routed through the blower to speed up steam raising and improve safety for the fireman by eliminating the tendency for blowbacks. So an attempt was made with an open ended pipe, placed in the chimney, to draw the fire. However the result was very little gas mixing and thus virtually no draw on the fire at all. Monarch Syndrome Video: Flash Video (.flv) format (1.54MB), Quicktime (.mov) format (1.67MB) & Windows Media Player (.wmv) Format (1.77MB) |
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Signalman Houghton waits to collect the single line staff from No. 823 'Countess'. Alongside is No.19. 05 May 2008 |
W&LLR No.14 rolls into Cyfronydd heading for Llanfair Caereinion as No.19 and driver Tickle wait to continue to Welshpool. 05 May 2008 |
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Sometimes it rains in Wales. No.14 waits for the rain to subside at Llanfair Caereinion, viewed from the footplate of No.19. 04 May 2008 |
The Welshpool & Llanfair Light Railway's website is at http://www.wllr.org.uk